GFS Power

DC Power System 48V, 24V or 12V…Site

Site Power System

Site Power System (SPS)

 12V, 24V and 48V DC Models

A complete DC power solution that integrates with batteries, loads, and monitors. The compact 300 watt assembly contains:

  • power supply with temperature compensation
  • automatic boost/float battery charge cycle
  • low voltage disconnect
  • programmable alarm contacts

Versatile installation options include:

  • Wall mount
  • 19″ Rack mount
  • DIN-Rail

High operating temperature rating with convection cooling make the unit ideal for:

  • Remote site shelters
  • Pole mount enclosure applications
  • Private network base stations
  • Microwave sites.

Ordering information:

  • SPS 12-20          13.6V (range 11-15V)      20Amp
  • SPS 24-10          27.2V (range 22-30V)      10Amp
  • SPS 48-6            54.0V (range 44-60V)      6Amp
  • Well regulated noise free 300 watt output – no interference with sensitive electronic loads

  • Separate Battery Charger output with remote temperature compensation sensor

  • Automatic Boost voltage output after AC power failure quickly recovers battery

  • Low voltage disconnect protects batteries from over discharge

  • Output current indicator LEDs

  • Wide temperature operating range (-10 to +60° C) with convection cooling – no fans to service

  • Alarm contacts interface with remote monitor systems

  • Active load sharing allows wiring in N+1 configuration for redundancy and/or in parallel for higher current capacity

  • Optional item – Rack and DIN-Rail mounting brackets


Models Input
All Models
All Models
SPS 12-20 100 – 275 VAC,
45 – 100 Hz.
12 20 12.25” W x 5.75” H x 2.45” D
SPS 24-10 24 10 (311mm x 146mm x 62mm)
SPS 48-6 48 6 3.4 Lbs./1.5 Kg.

Models SPS 12-20, SPS 24-10, & SPS 48-6

AC Input

Nominal: 110/220V, 45 – 100 Hz.
Voltage Range: 100-275V AC (full power output), 85-100V AC (reduced power output)
Frequency Range: 45 – 100 Hz.
Power Factor/Efficiency: >0.99 (full load)/87%
Input Fuses: Fuses in phase & neutral
Maximum Input Current: 4A @ 110 VAC, 2A @ 220 VAC
Input Voltage: Automatic shutdown, restarts automatically when correct voltage restored.
Input Rush: <2x maximum input current.

DC Output

SPS 12-20 SPS 24-10 SPS 48-6
Nominal Voltage: 12V 24V 48V
Rated Voltage: 13.6V 27.2V 54V
Voltage Range: 11-15V 22-30V 44-60V
Maximum Current: 23A 10A 6A

Redundancy/Scalability: Ok to wire in parallel, active load sharing
Temperature Compensation: Output voltage slope adjustable 0.1 to 0.2%/°C; 3′ cable with battery lug sensor provided
Line/Load: ±0.1%/±0.5% (no load to full load)
Hold-up Time: >15ms for 20% output voltage drop.
Start-up Time: Walk-in delay 2 seconds (depends on AC input voltage)


Current Limit: Adjustable to 50-100% of maximum rated current
Over Temp: Automatic current turndown, backup shutdown protection
Polarity Reversal: Output fuse with crowbar diode
Over Voltage: Adjustable limit
Noise: (under nominal conditions)
Ripple <100Hz: <5mV rms
Voice Band 100Hz to 5KHz: <1mV rms psophometric
Wide Band 5kHz to 1 MHz: <5mV rms
Peak to Peak 0 to 20MHz: <50mV p-p


Input to Output: 3000V AC
Input to Chassis: 2500V AC (VDR to chassis removed.)
Output to Chassis: 1500V AC


Cooling: Convection cooled
Range: -10° to +60°
Humidity: 5-95% RH (non-condensing)
Altitude: <7500m de-rate maximum ambient temperature by +4˚ C per 3000m above sea level


Case: Painted Aluminum
Mounting: Wall or enclosure back plane, vertical orientation
Dimensions: 12.25″ W x 6.40″ H x 2.45″ D; (311mm x 163mm x 62mm)
Weight: 3.4 lbs.;1.5kg


AC: IEC 320 universal connection, 3 foot power cord provided, NEMA 5-15R
Output to Load: 4 way lumberg macromodule, screw style
Output to Batteries: 4 way lumberg macromodule, screw style
 Temperature Sensor: 2 way lumberg macromodule, (pre-installed on 6 foot cable)
Monitor Connection: RJ45

Standard Features

Output Current Indicator: Ten segment red LED “dot” display

Auto Float/Boost:

Rectifier enters boost mode at power up. When battery current reduces to float threshold limit (adjustable from 0.1A to 40% MRC), unit reverts to float voltage setting. When in boost but out of current limit, rectifier will automatically switch back to float after approximately four hours. If battery current exceeds the float threshold limit when the rectifier is in float mode it will automatically switch to boost mode.

Alarm and Indicator Controls:

Positive V out, Load share signal (in/out), External shutdown, Open collector ‘off normal’ alarm (OSVD, over temp. limit), LVD synchronisation signal (in/out) Temperature compensation input signal, Open collector rectifier fail (via 4k7 resistor), Open collector mains fail, Negative V out

Low Voltage Disconnect:

SPS 12-20 SPS 24-10 SPS 48-6
Voltage Adjustment Range (Option*): 10-12V 19-24V 39-48V
* Activated by wiring configuration

Internal Alarm Card:

4x N.O or N.C (selectable) relay contacts with single common for rectifier fail, off normal, float low, float high. 1x VF changeover relay contact for mains fail. Relay contacts rated at 100V DC 1A. Connections via “mini combicon” connector accepts 16 AWG (1.5mm diameter) wire.

LED Indicators:

  • Green – AC on. (primary converter operating)
  • Green – Temperature probe connected and within normal limits.
  • Red – Rectifier ‘failed’.
  • Green – Rectifier in ‘float’ mode.
  • Yellow – Rectifier in ‘current’ limit.
  • Red – Rectifier ‘off normal’.

Internal Adjustments:

  • Float voltage
  • Boost voltage
  • Over voltage shut down
  • Current limit
  • Temperature compensation slope
  • Auto boost to float threshold limit
  • Load disconnect voltage
  • Load disconnect hysteresis voltage

Design Standards:

  • EN60950
  • Electrostatic Discharge: CISPR24
  • Radiated Radio Frequency: CISPR22
  • AC Harmonics: EN61000-3-2
  • AC Flicker and Fluctuation: EN61000-3-3
  • CE

Optional Equipment:

  • Rack mount Bracket
  • 19″, 4 RU (7 inches)
  • DIN-Rail Adapter Bracket

Specs subject to change.

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